Vertebrate animals feature a flexible, bony skeletal framework that provides the body shape, protects vital organs, and enables the body to move. The human skeleton comprises approximately 206 separate bones. These bones meet at joints, the majority of which are freely movable. The skeleton also contains cartilage for elasticity, and muscular ligaments consisting of strong strips of fibrous connective tissue for holding the bones together at their joints.
The femur, fibula, tibia, and metatarsal bones of the legs and feet support the body and therefore bear its weight. Muscles associated with the ilium, pubis, ischium, patella, tarsal, and phalanges bones provide the necessary bending of the hips, knees, ankles, and toes that are essential for humans to walk, run, climb, and engage in other locomotion activities.
Likewise, the humerus, ulna and radius bones and metacarpal and phalanges bones form the arms and hands, respectively. Muscles associated with the clavicle, scapula, and carpals enable the arm to bend or flex at the shoulder or elbow, and the hand to flex at the wrist and fingers, which is useful for lifting, carrying, and manipulating objects.
Over time, body bones or joints can become damaged. Bones fracture; ligaments tear; cartilage deteriorates. Such damage may result from the aging process, manifested by arthritis, osteoporosis, and slips and falls. But injuries are also caused by sports activities. For example, recreational and competitive running is enjoyed by some 37 million Americans with 25% of them suffering from running injuries annually.
Persons recovering from such injuries often suffer from gait and balance problems that must be addressed through physical therapy. Moreover, strokes and other neurological disorders frequently cause gait and imbalance problems too. Such persons often lack the strength and balance to rise from a sitting to a standing position. Nurses, physical therapists, aids, and other care providers must assist these people first in the simple skills of standing up and then walking. The therapist begins a physical therapy session with the patient seated in a wheelchair or on a chair, bed or therapy table. The patient then must transition to a standing position and then walk using an assistive device. But, the sit-to-stand motion is rapid with the movement typically being completed in less than 2.5 seconds, as shown by kinematic studies. See Kotake T, Dohi N, Kajiware T, Sum N, Koyama Y, Miura T, “An Analysis of Sit-to-Stand Movements”, 74 Archive Physical Medicine and Rehabilitation, 1095-99 (1993).
Gait therapy typically allows the therapist to assist with the movement of the legs and encourage patients to focus upon correcting their walking or running gait problems. Common physical therapy for such persons requires the therapist to manually manipulate the patient's legs to assist this learning process. But, physical therapists need an assistive device supporting the patient's body weight, while allowing access to the patient's legs during this gait therapy.
A number of different approaches have been taken within the industry and the medical community for treating these injuries or disorders. Exoskeletons entail external support systems made from strong materials like metal or plastic composite fibers shaped for supporting proper posture of the human body. Honda Motor Co. has employed “walking assist devices” for its automotive factory workers to support their bodyweight for reducing the load on assembly line workers' legs while they walk, move up and down stairs, and engage a semi-crouching position throughout a work shift. The U.S. military has experimented with exoskeletons for its soldiers to enable them to carry heavy equipment packs and weapons. However, the body must be connected to the exoskeleton at the limbs and other parts by means of straps and other mechanical attachment devices. The exoskeleton's motor must be regulated by various sensors and controls, and driven by hydraulics, pneumatics, springs, or other motorized mechanical systems. These can be cumbersome and expensive systems that do not necessarily reduce the stress on the body caused by gravity, and are difficult to manipulate during physical therapy or gait therapy sessions.
Athletes and older people suffering from joint injuries have rehabilitated in pools and water tanks. The buoyant property of the water provides an upwardly-directed force to the body that lightens the load otherwise directed to the joints. However, these types of systems are not portable, since the person is confined to the pool or water tank. Moreover, the resistance created by the water may interfere with physical therapy or gait therapy exercises.
Another approach is provided by a harness system exemplified by U.S. Pat. No. 6,302,828 issued to Martin et al. Consisting of an overhead frame to which is connected a raiseable body harness, such a system supports a portion of a person's body weight as he, e.g., walks or runs on a treadmill in order to diminish downward forces on the body joints. But the straps and attachment devices create localized pressure points and stresses on the body, and restrict the range of motion of the body and its limbs. Such a mechanical weight off-loading system may also lack portability. Again, such harness systems connected to stationary devices can interfere with physical therapy or gait therapy exercises.
The National Aeronautics and Space Administration (“NASA”) has developed a system that utilizes differential air pressure to provide a uniform “lift” to the body to assist an exercise process. See U.S. Pat. No. 5,133,339 issued to Whalen et al. The differential pressure is applied to the lower half of the person's body that is sealed within a fixed chamber to create a force that partially counteracts the gravitational force on the body. A treadmill contained within the sealed chamber allows the person to exercise. However, this Whalen system requires a large, immobile pressure chamber containing a treadmill. Such a system is expensive and requires cumbersome entry and exit by the person, which will not accommodate physical therapy or gait therapy. The system does not allow the therapist to access and manipulate the legs of the patient to provide this gait therapy.
Various mechanical assistive devices have been developed to assist therapists with the sit-to-stand movement in physical therapy and then function as a supportive walker during the physical therapy session. Ambulatory assist devices such as walkers and rollators are used to assist elderly or physically-impaired people undergoing rehabilitation, or people suffering from gait and balance problems due to strokes, Parkinson's and other neurological disorders. These devices are used to provide balance and some measure of body weight support often by the person using their arms and hands. Use of these devices requires the disabled person raise himself from a sitting position to a standing position in order to use the device to ambulate. However, physically impaired people often lack the upper body strength or balance in order to raise themselves from a sitting to a standing position without assistance. This prevents people from independently using ambulatory assist devices. Also providing personnel for assistance entails additional costs for rehabilitation institutions or in providing home care.
Walker devices that incorporate a means for assisting a seated person to stand are commercially available or otherwise known in the art. For example, U.S. Pat. No. 6,503,176 issued to Kuntz describes a walker-like device with a sling around the user's legs for supporting all or some of the person's weight. The support sling is raised and lowered by air cylinders on the sides of the device to which compressed air from an on-board tank is delivered via valves. But, the front frame of the walker and mechanisms on the front block the patient's legs from fully extending while walking and prevent the therapist from accessing the legs from the front of the device during a physical therapy or gait therapy session. Moreover, the air cylinder lift mechanisms and other components mounted on the sides of the device prevent access by the therapist to the patient's legs. Furthermore, the width of the device is not adjustable to fit a range of patient widths and heights that would be encountered in a physical therapy setting. Additionally, the device requires use of a compressed air cylinder for power, which is inconvenient to a user due to the weight, cost and impracticality of having to transport and refill compressed air tanks.
U.S. Pat. No. 8,468,622 issued to Purwar et al. shows a lifting apparatus that includes six bar mechanism linkages operated by an electro-mechanical actuator that moves in a particular J-shaped path while the patient is lifted from a sitting position to a standing position. However, these linkages are incorporated onto the sides of the device, which restricts access by the therapist to the patient's legs to work with them during gait therapy sessions. Moreover, a system with the electric motors and linkages will not be responsive enough to provide lift to support the patient's weight during over a two-second sit-to-stand lifting motion unless the motors are extremely large and powerful. This would result in a very heavy and bulky system, requiring large motors and heavy batteries. Nor does the front of device provide necessary clearance for the patient's legs to fully extend for longer strides. The device is also not adjustable to fit the range of patients typically encountered in a physical therapy setting. A typical seated height is approximately 18 inches.
U.S. Published Application 2013/0180557 filed by Triolo et al. describes a vertical-lift walker for assisting the patient's sit-to-stand transition motion. It includes a frame assembly having upper and lower frame portions. Wheels are provided beneath the lower frame to enable the walker to be propelled and maneuvered. A supporting upper frame platform fits under the patient's arms to provide support. The lifting force is provided by gas springs, which must be first manually compressed by the patient. The patient must first be in a standing position, and then use his body weight to compress the gas spring cylinders by sitting. But patients who cannot stand without assistance will find it difficult, if not impossible, to first stand up to compress these springs. Furthermore, these gas springs mounted to the sides of the walker block access to the legs of the patient from the sides.
U.S. Pat. No. 5,569,129 issued to Seif-Naraghi et al. describes a movable device for lifting and supporting patients undergoing partial weight support gait training. The device has a U-shaped lower base which is sufficiently wide to fit around a treadmill or wheelchair. The patient wears a harness which is attached to an overhead beam that is raised and lowered by an electric motor and on-board battery. The U-shaped base is very long and wide in comparison with other assistive devices like a walker, thereby making it very hard to navigate and maneuver the device in therapy settings. Other harness-lift systems available in the market include the “New Lift Walker” sold on newliftwalker.com, and the “Lite Gait” system sold by Mobility Research, P.O. Box 3141, Tempe, Ariz. See also U.S. Pat. No. 6,302,828 issued to Martin et al. But these devices tend to be large, bulky, and cumbersome without maneuverability. While the harness systems provide some degree of body weight offloading, the patient still is required to use his upper body strength to physically lift him up from a seated position. However, many physical therapy patients lack this necessary upper body strength. Furthermore, the harness attached to the upper torso of the patient restricts the natural position of the body during running and walking to a forward leaning position, and during the sit-to-stand motion. Because harness systems pull the upper body directly upwards from the chest, they can provide too much stability for balance training. Another issue with the harness-based body weight support is that the harness supporting the subject decreases the need for natural associated postural adjustments (“APAs”) that are required for independent gait. The main site for an active control of balance during gait is the step-to-step mediolateral placement of the foot. When supported by a harness during training, any mediolateral movement is restricted by a medially-directed reaction force component that will help stabilize the body in the frontal plane, and decrease or even eliminate the need for APAs, thereby making gait and balance training less effective. Moreover, the straps and attachment devices create localized pressure points and stresses on the body, and restrict the range of motion of the body and its limbs. In particular the straps around the thighs and groin interfere with the back and forth rotation of the legs.
A new alternative to a harness-based body weight support is a close-fitting differential pressure suit as described in this application and in U.S. Published Application 2010/0000547. A differential pressure body suit with external support against body suit migration is provided by the invention. In its preferred embodiment, such body suit may comprise a close-fitting, multi-layered suit sealed against a person's skin to contain the differential pressure, or a looser-fitting space suit that bends at the joints with minimal force. External support means include either fixed or movable mechanical supports attached to the body suit, extraordinary air pressure levels for making the body suit rigid, or exoskeletons attached to the body suit. This differential pressure body suit provides a portable and convenient system for rehabilitating a skeletal joint injury or training for injury prevention or athletic performance. The pressurization reduces the weight of the body to greater or lesser extents, and offloads the weight to the ground through the external support means. The body suit is flexible and has joints that can flex with minimal force even under pressure.
Pressurized bodysuits have also been used within the industry for several different applications. For example, U.S. Published Application 2002/0116741 filed by Young discloses a bodysuit with integral supports and internal air bladders that are filled with pressurized air. This air pressure exerts force against the muscles of a person wearing the suit to tone them during daily activities. U.S. Pat. No. 6,460,195 issued to Wang illustrates exercise shorts with buckled belts, air bags, and a vibrator that directs pulses of pressurized air to the body to work off fat and lift the hips. U.S. Pat. No. 3,589,366 issued to Feather teaches exercise pants from which air is evacuated, so that the pants cling to the body of an exerciser to cause sweating, thereby leading to weight loss.
The U.S. military has also employed pressurized suits of various designs for protecting fighter pilots from debilitating external G-forces. Due to rapid changes in speed and direction, the fighter pilot's body undergoes very high accelerations. This normally forces the pilot's oxygen-laden blood away from the portion of the circulatory system between the heart, lungs and brain, pooling instead toward the blood vessels of the lower extremities. As a result, the pilot can lose situational awareness and spatial orientation. A pilot's bodysuit pressurized against the blood vessels of the legs can force the oxygen-laden blood back to the head and torso of the pilot. See U.S. Pat. No. 2,762,047 issued to Flagg et al.; U.S. Pat. No. 5,537,686 issued to Krutz, Jr. et al.; and U.S. Pat. No. 6,757,916 issued to Mah et al. U.S. Pat. No. 5,997,465 issued to Savage et al. discloses a pants bodysuit made from metal or polymer “memory material” that is heated by electrical current to form around the body, and then cooled to apply pressure for treating this G-forces phenomenon.
Pressurized bodysuits have been used previously for other purposes, such as splinting leg fractures, stopping bleeding from wounds, treating shock, and supporting the posture of partially paralyzed patients. See, e.g., U.S. Pat. No. 3,823,711 issued to Hatton; U.S. Pat. No. 3,823,712 issued to Morel; U.S. Pat. No. 4,039,039 issued to Gottfried; and U.S. Pat. No. 5,478,310 issue to Dyson-Cartwell et al. Bodysuits can also have air between the suit and the body evacuated by vacuum to draw the suit into close contact with the body. See U.S. Pat. No. 4,230,114 issued to Feather; U.S. Pat. No. 4,421,109 issued to Thornton; and U.S. Pat. No. 4,959,047 issued to Tripp, Jr. See also U.S. Published Application 2006/0135889 filed by Egli.
But, such pressurized body suits have not previously been used to rehabilitate skeletal joint injuries. Moreover, they have typically been used only in stationary situations like a sitting pilot due to the problem of air pressure forcing the body suit off the lower torso. In some applications like weight-loss patients, suspender straps have been required to overcome this downwards migration of the bodysuit pants.
In either harness-based or partial pressure differential pressure suit approaches, means are required for attaching the harness, pressure suit or other attaching means to the mechanism that provides the counter-force body weight support. Harness systems use ropes straps and or cables to attach the harness system to the overhead counter-weight system. A natural walking or running gait consists of body movements or rotations about various axes of the body. It is important that the connecting system not unduly restrict these movements. There is a need for body weight support systems that do not restrict natural body movements.
Thus there is a need for a walker device that can provide body weight offloading and lift support throughout the range of the sit-to-stand movement. Once standing, the patient then should be able to walk with the supportive walker device while undergoing gait therapy by the therapist. A pressurized bodysuit that can worn by the patient to apply localized differential pressure to a lower body part, coupled with the walker external support and a pressure condition control system would be beneficial, particularly due to its portable nature. The walker device also should be easily maneuverable by the therapist or patient during the walking portion of gait therapy.